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【单选题】
将信号f(t)变换为( )称为对信号f(t)的尺度变换。A.
f(-t)
B.
f(t–k 0 )
C.
f(t–t 0 )
D.
f(at)
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皮皮学刷刷变学霸
举一反三
【单选题】各种车辆和行人通过电气化铁路平交道口必须遵守：通过道口车辆上部或其货物装载高度（从地面算起）超过（）米通过平交道口时，车辆上部及装载货物上严禁坐人。
A.
2
B.
3
C.
4
D.
4.5
【单选题】What tools were used to dig holes to lay the wooden stumps?
A.
Cow jaw-bones.
B.
Sharp rocks
C.
Aliens
D.
Deer antlers
【简答题】A．The clay was placed in molds. B．Special tools were used to shape the clay. C．Each person was responsible for a particular part of the process. D．It was created on pottery wheels.
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